The present disclosure relates generally to fluid level indicators and more particularly to an electronic fluid level indicator.
Various electronic fluid level indicators have been used in the automotive vehicle industry for determining if a proper amount of oil is in an engine sump or oil pan. One conventional electronic fluid level indicator has a single elongated opening in a printed circuit board within which a six inch long resistive wire is secured by a spring. The printed circuit board and wire are located within a hollow tube.
Another traditional approach employs an elongated polymeric overmolding upon stamped and conductive metal circuits with a resistive wire attached thereto; these are retained within a polymeric housing. Examples of such traditional devices are disclosed in the following U.S. Pat. No. 6,578,415 entitled “Limit-Level Sensor and Method of Determining the Undershooting or Overshooting of an Intended Level of Liquid in a Container” which issued to Schimmel et al. on Jun. 17, 2003; U.S. Pat. No. 6,548,283 entitled “Sensor for Determining the Level and Temperature of a Liquid” which issued to Acht et al. on Apr. 8, 2003; U.S. Pat. No. 5,210,769 entitled “Liquid Level Measuring System” which issued to Seidel et al. on May 11, 1993; and U.S. Pat. No. 4,679,432 entitled “Probe for Measuring the Level of a Liquid” which issued to Draeger on Jul. 14, 1987; all of which are incorporated by reference herein. These prior devices are prone to premature failures due to vibration of the unsupported resistive wire and/or thermistor.
In accordance with the present invention, an electronic fuel level indicator includes an elongated circuit board containing multiple elongated slots separated by a land segment of the circuit board, and an elongated wire spanning across the slots and being clamped to the land segment. Another aspect provides at least one elongated polymeric and/or insulating cover retained against a circuit board and a portion of the wire solely by insertion of the circuit board and cover within an elongated hollow tube through which fluid may flow. A method of assembling an electronic fluid level indicator is also provided.
The present electronic fluid level indicator is advantageous over prior devices in that the present electronic fluid level indicator allows for a longer length of circuit board and/or resistive wire to be employed, thus, improved resistance sensing, while also reducing vibrational failure modes. Furthermore, the present electronic fluid level indicator advantageously provides improved fluid inlets, outlets and internal channels thereby allowing improved fluid flow access to the resistive wire and temperature sensor. The resistive wire of the present electronic fluid level indicator also requires less resistance per foot than traditional constructions. Moreover, the present construction leads to less expensive assembly. Additional features and benefits of the present invention will become apparent from the following description and appended claims, taken in conjunction with the accompanying drawings.